device for controlling a first tillsatsbroms in a vehicle, and a braking system for a vehicle

摘要

The invention relates to a device for controlling an auxiliary brake of a heavy vehicle. The auxiliary brake consists, for example, of a retarder, which is controlled by a chosen braking force instead of being controlled by a certain braking moment, which is conventional. This makes it possible that the retarder is experienced to brake satisfactorily also when the retarder is provided in a vehicle driven by an engine with a low engine speed and where the end gear of the vehicle thereby is dimensioned with a high gear ratio. Herefore, the device comprises means (12, 18) arranged to make it possible for the driver to define a desired braking force at the driving wheels (2c-2d), and a control unit (11), which, when the driver has defined a desired braking force at the driving wheels (2c-2d), is arranged to calculate the brake action of the retarder (3), which substantially corresponds to the desired braking force and thereby to control the retarder (3) in such a manner that the calculated brake action is achieved.